-er a-a a-b aaa aab aae aah aao aar aas ab- aba abb abe abh abo abr abs aea aeb aee aeh aeo aer aes aha ahb ahe ahh aho ahr ahs aoa aob aoe aoh aoo aor aos ar- ara arb are arh aro arr ars as- asa asb ase ash aso asr ass baa bab bae bah bao bar bas bba bbb bbe bbh bbo bbr bbs be- bea beb bee beh beo ber bes bha bhb bhe bhh bho bhr bhs boa bob boe boh boo bor bos bra brb bre brh bro brr brs bsa bsb bse bsh bso bsr bss eaa eab eae eah eao ear eas eba ebb ebe ebh ebo ebr ebs eea eeb eee eeo eer ees eha ehb ehe ehh eho ehr ehs eo- eoa eob eoe eoh eoo eor eos era erb ere erh ero err ers es- esa esb ese esh eso esr ess haa hab hae hah hao har has hba hbb hbe hbh hbo hbr hbs he- hea heb hee heh heo her hes hha hhb hhe hhh hho hhr hhs hoa hob hoe hoh hoo hor hos hr- hra hrb hre hrh hro hrr hrs hsa hsb hse hsh hsr hss oaa oab oae oah oao oar oas ob- oba obb obe obh obo obr obs oea oeb oee oeh oeo oer oes oha ohe ohh oho ohr ohs oo- ooa oob ooh ooo oor oos or- ora orb ore orh oro orr ors os- osa osb ose osh oso osr oss ra- raa rab rae rah rao rar ras rba rbb rbe rbh rbo rbr rbs re- rea reb ree reh reo rer res rh- rha rhb rhe rhh rho rhr rhs roa rob roe roh roo ror ros rra rrb rrh rrr rrs rsa rsb rse rsh rso rsr rss saa sab sae sah sao sar sas sba sbb sbe sbh sbo sbr sbs se- sea seb see seh seo ser ses sh- sha shb she shh sho shr shs soa sob soe soh soo sor sos sr- sra srb sre srh sro srr srs ss- ssa ssb sse ssh sso ssr sss